Electric circuit recloser



June 15, 1965 M. L. HEINTZ- ELECTRIC CIRCUIT RECLOSER Filed March 28, 1963 IN VENTORI MILTON L. HE/NTz,

A TTORNE Y.

United States Patent 3,189,708 ELECTRIC CIRCUIT RECLOSER Milton L. Heintz, Newtown fiqnare, Pap, assignor to General Electric Company, a corporation of New York Filed Mar. 28, 1963, Ser. No. 268,737 3 Claims. (Cl. 200-89) This invention relates to an electric circuit recloser and, more particularly, to a recloser of the type that relies upon electromagnetic means for opening the recloser and overcenter spring means for closing it when the magnetic means is reset to its normal position after an opening operation.

In such a recloser the over-center spring means customarily holds the movable contact of the recloser in its fully open position during the first stages of the resetting operation of the electromagnetic means. However, when the resetting operation has proceeded to a predetermined intermediate point, the overcenter spring means becomes elfective to snap the movable contact into its closed position at a high speed essentially independent of the speed at which the electromagnetic means is resetting. Thus, by relying upon spring means of the overcenter type, it is possible to eifect high speed contact-closing despite the low reset speed of the controlling electromagnetic means.

The driving force exerted by an overcenter spring on a driven member typically is at a minimum when a spring is at dead center and builds up .as the spring departs from dead center. Thus, if the overcenter spring means is to be capable of exerting a substantial closing force on the movable contact when approaching the fully closed position and thus of driving the contact at the desired high speed during this interval, it is desirable that the overcenter spring means pass over center at an intermediate point in the reset stroke of the electromagnetic means rather than at the very end of the reset stroke. Such a relationship, however, tends to permit the high speed movable contact to reach fully-closed position before the slow resetting speed electromagnetic means has completed its resetting stroke.

If a fault is present on the line when the movable con'tact reaches its closed position, the electromagnetic means will be operated by the fault current and complete resetting of the electromagnetic means will be prevented if such resetting has not already been completed. This can .be detrimental to proper functioning of the recloser because proper functioning depends upon the electromagnetic means being fully reset When operation is initiated. 'If only partial resetting has occurred, the intended time delay on reopening will be objectionably shortened and there may also be a failure of the recloser to produce the desired advancement of its operation-counter or sequencer.

Accordingly, an object of our invention is to provide a circuit recloser in which complete resetting of the electromagnetic means can occur despite the fact that the overcenter spring means for closing the contacts is shifted overcenter at an intermediate point in the resetting operati-on.

Another object is to delay reclosing motion of the movable contact until the end of the resetting operation for the electromagnetic means without necessitating an increase in the size of the overcenter spring needed to drive the contacts closed against maximum rated currents.

In carrying out my invention in one form, I provide a first contact and a second contact movable into and out of engagement with said first contact. Coupled to the first contact is an arm that is mounted for pivotal movement about a fixed axis. Motion of this arm is controlled by electromagnetic means that comprises an actuating part movable from a normal position into a displaced position in response to energization of the electromagnetic means 3,189,708 Patented June 15, 1965 by overcurrents. Means is provided for moving the contact-coupled arm from a contact-closed position into a fully-open position in response to motion of said actuating part from its normal to its displaced position. Means is also provided for moving the contact-coupled arm from its fully-open position to its contact-closed position in response to return of said actuating part to its normal position. This latter means comprises an overcenter spring coupled to the arm and biasing the arm in a con tact-closing direction when its line of action is on one side of said axis and in a contact-opening direction when its line of action is on the other side of said axis. The overcenter spring is located on said other side of the axis when the second contact is in fully-open position and is shifted to said one side when the actuating member moves through an intermediate point in a closing stroke. A latch is provided for holding the contact-coupled arm in approximately its fully-open position. This latch is effec tive to maintain said arm in said fully-open position while said overcenter spring is on said one side of said axis during a closing operation. The latch is controlled by means responsive to return of the actuating member to its normal position. This latter means releases the latch when the actuating member has traveled a substantial distance beyond said intermediate point and has reached a point closely adjacent its normal position. The release point for the latch is postponed sufliciently during a closing operation .to allow the actuating part to reach substantially its normal position before the contacts engage during closing.

For a better understanding of my invention, reference may be had to the following specification taken in conjunction With the accompanying drawings, wherein:

FIG. 1 is a cross sectional view of a portion of a circuit recloser embodying one form of my invention. The recloser is shown in a fully closed position.

FIG, 2 is a cross sectional view along the line 2-2 of FIG. 1.

FIG. 3 is a diagrammatic view of the recloser of FIG. 1.

FIG. 4 is a view similar to that of FIG. 1 except showing the parts of the recloser in their fully open position.

Referring now to FIG. 1, the interrupter shown therein comprises a metallic tank 7 filled with a suitable insulating oil 8. A stationary frame 16 of insulating material is suspended from a portion of the tank by suitable insulating rods 9.

Mounted on the frame 16 are two stationary contact assemblies 10 disposed in laterally spaced-apart relationship, as best seen in FIG. 2. These stationary contact assemblies 10 are connected together in series-circuit relationship by a conductive crossbar 11 having terminal portions 12 at its opposite ends constituting the movable contacts of the interrupter. Each of these contacts 12 is movable into and out of engagement with its mating stationary contact assembly 10 along the arcuate path 13 shown in FIG. 1.

As will be apparent from FIGS. 1 and 2, each stationary contact assembly 10 comprises a conductive stud 14 and a contact finger 15 pivotally mounted on the stud 14. The stud extends through a staionary frame 16 of insulating material and is fixedly mounted thereon. Preferably, the mounting comprises a nut 17 threaded onto the upper end of the stud and clamping the frame 16 between the nut and a shoulder provided on the stud. Referring to FIG. 1, the contact finger 15 is pivotally mounted at its upper end on the stud 14 and is biased to the right by a compression spring 20. This compression spring 20 is preferably carried by a guide pin 22 extend-ing freely through a suitable opening in the finger contact 15. The compression spring 2c is disposed between a stop 24 on the pin 22 and the movable contact 15. The lower end 2% of the contact 15 is preferably provided with a facing 26 of arc-resistant material which bears against the movable contact 12 during the early stages of opening movement and the final stages of closing movement.

The conductive cross-bar 11 and the movable contacts 12 at the ends of the crossbar 11 are carried by laterallyspaced actuating arms 31) of insulating material. As shown in FIG. 1, these arms 35} are pivotally mounted at their left hand end on stationary pivots 31 that are cartried on a supporting bracket 32 fixed to the stationary frame 16. The arms 30 are coupled together by a pin 36 that extends between the arms and is fixed to each arm to maintain a fixed lateral spacing between the arms 30. The movable contacts 12 are prevented from shifting laterally with respect to the actuating arms by suitable cotter pins 33 and washers 35 disposed at the inner side of each of the actuating arms 30.

A portion of the force for holding the movable contact 12 in its fully-closed position shown in FIG. 1 is derived from a tension-type overcenter spring 34. This overcenter spring 34 is connected between the pin 36 and another pin 38 carried at the upper end of a guide link 40 that is pivotally mounted on a stationary pivot 42. So long as the longitudinal axis, or line of action, of the spring 34 is above the pivot 31, the spring 34 urges the contact arms 30 in a counterclockwise closing direction, but when the axis of spring 34 is shifted below the axis of pivots 31, the spring 34 urges the contact arms as in a clockwise opening direction about their pivot 31.

The force for opening the contacts is derived from a solenoid 50 comprising a vertical-1y movable armature 51 and a stationary coil 52 connected in series with the 7 contacts 10, 12 by suitable conductive means, such as shown at 53 in the schematic view of FIG. 3. When current above a predetermined pick-up value flows through the coil 52, sutficient magnetic force is developed to drive the armature 51 in a downward direct-ion from its position of FIG. 1. This downward motion is imparted to a pin 54- carried by a force-transmitting lever 55 pivotally mounted on a stationary pivot 56. The pin 54 responds by moving downwardly, causing the force-transmitting lever 55 to pivot in a clockwise direction about its stationary pivot 56. After a predetermined amount of travel in a clockwise direction, the force-transmitting lever 55 moves into the dotted line position of FIG. 1 and a cam surface 58 on the lever 55 impacts against the pin 36, driving the actuating arms 30 clockwise about their pivots 31. When this clockwise motion of the actuating arms 30 has shifted the longitudinal axis of spring 34 downwardly past the axis of pivots 31, the spring 34 is free to contact and drive the actuating arms 30 further in a clockwise direction to complete their opening stroke.

The position of the parts at the end of an opening stroke is shown in FIG. 4, where the overcenter spring 34 is shown positioned below the axis of the pivot 31 of the actuating arms 30. So long as the armature 51 remains depressed, this spring 34 is maintained in this position of FIG. 4 by a link 60 pivotally connected between the guide link 41 and the force-transmitting lever 55. So long as the overcenter spring 34 is positioned below the axis of pivot 31, it acts in a direction to maintain the actuating arms 30 and the contacts 12 in their fully-open position of FIG. 4.

To provide an additional means for holding the contacts 12 in their fully-open position, a latch 62 is provided. This latch 62 is mounted for pivotal motion about a stationary pivot 63 and is biased in a clockwise direction about this pivot 63 by means of a suitable torsion spring 64. When the contacts 12 are in their fully-closed position of FIG. 1, the latch 62 is maintained in a retracted position shown in FIG. 1 by means of an extension 65 provided on the lower end of guide link 10. This extension 65 bears against a projecting portion of the latch 62 and thus maintains the latch in its retracted position of FIG. 1 when the contacts are closed.

When the force-transmitting lever 55 is moved in a clockwise opening direction about its stationary pivot 56 from the position of FIG. 1, the guide link is rotated in a counterclockwise direction about its stationary pivot 42. This lifts the extension 65 out of engagement with the projecting part of the latch 6-2, permitting the latch torsion spring 64 to drive the latch 62 clockwise into engagement with a stationary stop 67. Accordingly, when the contacts 12 are driven open at a subsequent stage of the opening operation, the latch 62 is in readiness to receive the pin 36., As it approaches the fully open position, the pin 36 brushes the latch 62 aside, but further opening movement of pin 36 enables the latch spring 67 to force the hooked upper end of the latch into place behind the pin 36. The parts are then in their fully open position of FIG. 4, where the latch 62 can be seen in its fully-latched position with respect to the pin 36.

After the circuit through the contacts 10, 12 has been interrupted, the solenoid armature 51 is free to beg-in returning in an upward direction toward its normal position of FIG. 1 under the influence of the overcenter spring 34. This spring 34, in contracting, draws the lines 40 and 60 from their position of FIG. 3 into a more aligned position, forcing the armature 51 upwardly. This upward movement of the armature 51 allows the over-center spring 34 to rotate the guide link 40 in a clockwise direction about its stationary pivot 42. When pin 38 has moved in a clockwise direction suificiently to carry the longitudinal axis of the spring 34 upwardly past the axis of pivot 31, the spring 34 begins acting in a direction to drive the contact-actuating arms 30 counterclockwise about their pivots 31 through a counterclockwise closing stroke. If the latch 62 were not present, the spring 34- immediately after passing above the axis of pivots 31, would quickly drive the actuating arms 36 upwardly toward closed position. But the latch 62 acts to delay the start of this closing motion of the actuating arms 35 to a point long past the point at which overcenter spring 34 passes over center. It is not until the solenoid armature 51has almost reached the very end-of its upward resetting stroke that the latch 62 is released. This latch-release is effected bythe extension e 65, which finally engages the projecting portion of the latch 62 and thus pivots it counterclockwise from its position of FIG. 4. When the latch is released, the overcenter spring 34 responds by quickly driving the contact actuating arms 30 together with the contacts 12 into their closed position of FIG. 1.

The primary purpose of the latch 62 is to delay reestablishm-ent of the circuit through the contacts 10, 12 until the solenoid armature 51 can be substantially completely reset to its normal position of FIG. 1. This is desirable because if .a fault is still present on the power circuit when the contacts 10, 12 reclose, then the coil 52 of the solenoid will be immediately reenergized and the armature will again be driven in a downward opening direction without having been first restored to its normal position. This would mean that the armature 51 would move through only a partial stroke on this opening operation.

In a recloser of the type disclosed, failure of the solenoid armature 51 to move through .a full stroke on opening can be detrimental to proper functioning of the recloser. This follows from the fact that opening opertaions of the disclosed recloser are time delayed to provide for coordination of the operation of the various protective devices in the power circuit. 7 The duration of this time delay is controlled by retarding the downward motion of solenoid armature 51. This is typically done by providing a metering orifice (not shown) in a passage such as communicating with the oil 81 beneath the enlarged piston-like portion of the armature 51. Downward movement of the armature 5:1 forces this oil 81 upwardly past the armature, through the passage 80, and then through the metering orifice (not shown). It should be apparent that the length of this time-delay period depends upon the length of the armature stroke, and thus a substantial shortening of the stroke will reduce the length of the time delay period. This can prevent the recloser from coordinating with other protective devices that have been preset in accordance with the delay that would result from a full stroke of armature 5.1.

Also, a recloser typically has operation-counting means (not shown) that causes it to lock out afiter a predetermined number of closely-successive ope-rations indicative of a persistent fault. Usually such operation-counting means performs in the intended manner only if the armature executes a full stroke on each opening operation. Thus, it will be .apparent that failure of the armature 51 to execute a full stroke on one or more opening operations would interfere with the reclosers locking out in the intended manner in the event of a persistent fault.

I have assured that the armature 51 will execute a full stroke on each opening operation by allowing the armature 51 to return almost to its fully reset position before the latch 62 is released. Thus, when the contacts 12 do reach their fully closed position, the armature 51 will have been restored to its normal position in readiness for a new operation in the event of a persistent fault. In a typical recloser having a two-inch resetting stroke for the armature, the overcenter spring 34 passes across the axis of pivot 31 approximately one inch before the armature reaches the fully-reset position and the latch is tripped about inch or even less before the armature reaches this fully-reset position.

Although it would be possible to effect the desired delay in closing motion of the movable contact by designing linkage 3-2 so that overcenter spring 34 passed over center only at the very end of the closing stroke, this approach has a basic disadvantage. In this respect, an overcenter spring has a very short efiective lever arm when it is near the dead center position. Substantial movement past dead center is required to permit this effective lever arm and the force resulting therefrom to build up to the desired level. Thus, if the overcenter spring were allowed to pass over center only near the end of the armature resetting stroke, there would be no opportunity for the closing force tobuild up to the desired level. This lower closing force would interfere with closing against short circuits and also with holding the contacts closed against high momentary currents, as is usually desired. The lower closing force would also interfere with acceleration of the movable contacts to the desired high speed as they approach their closed position. This closing force could be made higher by using a heavier overcenter spring 34, but this would necessitate a larger and more expensive solenoid for overcoming the overcenter spring during opening, particularly for those currents just above the minimum pick-up current.

In the disclosed recloser, I have obtained added force for holding the contacts closed under high momentary currents by providing a spring 69 separate from the overcenter spring 34, which biases the movable contacts 12 in a closing direction. This spring 69 is preferably a torsion spring encircling the fixed pivot 31. During an opening operation, this separate spring 69 acting on the actuating arms 30 does not oppose initial movement of the force-transmitting lever 55 out of its normal position since such initial movement takes place independently of the actuating arms 30. It is only after the cam surface 58 of the force-transmitting lever 55 engages the pin 36 that the solenoid 50 is required to act against spring 69. By this time the solenoid armature has developed enough momentum to easily overcome the closing bias of spring 69 and drive the contacts open at high speed. Had the added closing force been obtained from using a heavier overcenter spring 34 instead of from the separate spring 69, then the solenoid 50 would have been required to act against the heavier overcenter spring from the start of its opening movement, and this would have necessitated a larger and more expensive solenoid.

The presence of latch 62 enables this separate spring 69 to be much stronger than it could be without the latch 62. In this respect, if there were no latch, then a strong spring 69 could immediately drive the contact-actuating arms 30 into closed position upon deenergization of solenoid 50 at the end of an opening operation or at least could drive the arms 30 through a closing stroke before the overcenter spring 34 reached dead center during closing. But with the latch 62 present, even such a strong spring at 69 is prevented from driving the arms 30 through a closing stroke until the latch 62 is tripped near the end of the armature-resetting operation.

As an additional aid in holding the contacts closed against high momentary currents, a U-shaped structure 71 of magnetizable material is preferably provided between the two stationary contacts 10. This structure 71 is fixed to a block 76 of insulating material that is fixed to the stationary frame 16. The magnetizable U-shaped structure 71 has a recess therein that receives the cross bar 11 when the cross bar enters the contact-closed posi tion. When the cross bar is in or near the recess, there is a magnetic force tending to move the cross bar upwardly toward fully closed position with a force that varies directly with current magnitude. This U-shaped magnetizable structure is disclosed and claimed in Patent No. 3,065,317, Streater, assigned to the assignee of the present invention, and reference may be had to that patent if more details as to the structure and its operation are desired.

While I have shown and described a particular embodiment of my invention, it will be obvious to those skilled in the art that various changes and modifications may be made without departing from my invention in its broader aspects, and I, therefore, intend in the appended claims to cover all such changes and modifications as fall within the true spirit and scope of my invention.

What I claim as new and desire to secure by Letters Patent of the United States is:

1. A circuit recloser comprising:

(a) a first contact,

(b) a second contact movable into and out of engagement with said first contact,

(0) an arm coupled to said second contact and mounted for pivotal movement about a fixed axis,

(d) electromagnetic means comprising an actuating part movable from a normal position to a displaced position in response to energization of said electro magnetic means by overcurrents,

(e) means for moving said contact-coupled arm from a contact-closed position into a fully open position in response to motion of said actuating part from its normal to its displaced position,

(f) means for moving said contact-coupled arm from its fully-open position to its contact-closed position in response to return of said actuating part of said normal position,

(g) said latter means comprising an overcenter spring coupled to said arm and biasing said arm in a contact-closing direction when its line of action is on one side of said axis and biasing said arm in a contact-opening direction when its line of action is on the other side of said axis,

(h) said overcenter spring being located on said other side of said axis when the second contact is in fullyopen position and being shifted to said one side when said actuating member moves through an intermediate point in a closing stroke.

(i) latch means for holding said arm in approximately its fully-open position and elfective to maintain said arm in said approximately fully-open position while said overcenter spring is on said one side of said axis during a closing operation,

(j) and means responsive to return of said actuating member toward its normal position for releasing said latch means when said actuating member has traveled a substantial distance beyond said intermediate point and has reached a point closely adjacent its normal position,

(k) the release of said latch means being postponed sufficiently during a closing operation to allow said actuating part to reach substantially its normal position before said contacts engage during closing.

2. The recloser of claim 1 in which during an opening operation said actuating part moves through a predetermined travel before applying opening force to said movable contact, and in which auxiliary spring means separate from said overcenter spring means is provided for biasing said movable contact in a closing direction, said actuating part being movable through said predetermined travel before encountering the opposing force of said auxiliary spring means.

o o 3. The recloser of claim 1 in which the means for moving said contact-coupled arm inra closing direction comprises a guide link for carrying one end of said overcenter spring across said axis during a closing operation, and in which means coupled to said guide link is provided for effecting release of said latch means.

References Cited by the Examiner UNITED STATES PATENTS 1,429,948 9/22 Hulse 200-106 3,065,317 11/62 Streater 200-87 BERNARD A. GILHEANY, Primary Examiner. ROBERT K. scHAEEER, Eaaminer, 

1. A CIRCUIT RECLOSER COMPRISING: (A) A FIRST CONTACT, (B) A SECOND CONTACT MOVABLE INTO AND OUT OF ENGAGEMENT WITH SAID FIRST CONTACT, (C) AN ARM COUPLED TO SAID SECOND CONTACT AND MOUNTED FOR PIVOTAL MOVEMENT ABOUT A FIXED AXIS, (D) ELECTROMAGNETIC MEANS COMPRISING AN ACTUATING PART MOVABLE FROM A NORMAL POSITION TO A DISPLACED POSITION IN RESPONSE TO ENERGIZATION OF SAID ELECTROMAGNETIC MEANS BY OVERCURRENTS, (E) MEANS FOR MOVING SAID CONTACT-COUPLED ARM FROM A CONTACT-CLOSED POSITION INTO A FULLY-OPEN POSITION IN RESPONSE TO MOTION OF SAID ACTUATING PART FROM ITS NORMAL TO ITS DISPLACED POSITION, (F) MEANS FOR MOVING SAID CONTACT-COUPLED ARM FROM ITS FULLY-OPENED POSITION TO ITS CONTACT-CLOSED POSITION IN RESPONSE TO RETURN OF SAID ACTUATING PART OF SAID NORMAL POSITION, (G) SAID LATTER MEANS COMPRISING AN OVERCENTER SPRING COUPLED TO SAID ARM AND BIASING SAID ARM IN A CONTACT-CLOSING DIRECTION WHEN ITS LINE OF ACTION IS ON ONE SIDE OF SAID AXIS AND BIASING SAID ARM IN A CONTACT-OPENING DIRECTION WHEN ITS LINE OF ACTION IS ON THE OTHER SIDE OF SAID AXIS, (H) SAID OVERCENTER SPRING BEING LOCATED ON SAID OTHER SIDE OF SAID AXIS WHEN THE SECOND CONTACT IS IN FULLYOPEN POSITION AND BEING SHIFTED TO SAID ONE SIDE WHEN SAID ACTUATING MEMBER MOVES THROUGH AN INTERMEDIATE POINT IN A CLOSING STROKE. (I) AND MEANS FOR HOLDING SAID ARM IN APPROXIMATELY ITS FULLY-OPEN POSITION AND EFFECTIVE TO MAINTAIN SAID ARM IN SAID APPROXIMATELY FULLY-OPEN POSITION WHILE SAID OVERCENTER SPRING IS ON SAID ONE SIDE OF SAID AXIS DURING A CLOSING OPERATION, (J) AND MEANS RESPONSIVE TO RETURN OF SAID ACTUATING MEMBER TOWARD ITS NORMAL POSITION FOR RELEASING SAID LATCH MEANS WHEN SAID ACTUATING MEMBER HAS TRAVELED A SUBSTANTIAL DISTANCE BEYOND SAID INTERMEDIATE POINT AND HAS REACHED A POINT CLOSELY ADJACENT ITS NORMAL POSITION, (K) THE RELEASE OF SAID LATCH MEANS BEING POSTPONED SUFFICIENTLY DURING A CLOSING OPERATION TO ALLOW SAID ACTUATING PART TO REACH SUBSTANTIALLY ITS NORMAL POSITION BEFORE SAID CONTACTS ENGAGE DURING CLOSING. 